1. Field of the Invention
The present invention relates to a vulcanizing machine for manufacturing pneumatic tires and, in particular, to a vulcanizing machine that is provided with an exchangeable segmented mold for selectively producing tires of different sizes or specifications.
2. Description of the Related Art
In the tire industry, it is a recent trend to use vulcanizing machines with segmented molds for manufacturing pneumatic tires, in particular high performance radial tires. Typically, a segmented mold includes a plurality of tread mold pieces for defining the outer contour of a tire tread portion, and upper and lower side mold members engaged with the tread mold pieces, for defining the outer contours of tire sidewall portions. The tread mold pieces are detachably connected to respective connector segments which are slidably engaged with a container ring so that vertical movement of the container ring causes radial movement of the connector segments relative to the tread mold pieces. Such segmented mold is disclosed, for example, in U.S. Pat. Nos. 4,872,822 and 4,883,415.
In order to achieve a satisfactory manufacturing productivity of tires, however, known vulcanizing machine requires further improvement. Specifically, besides a complicated structure arising from a large number of associated components and a high initial cost, there is a serious a problem that substantial labor and time are required for manually assembling or disassembling the segmented mold when, for example, changeover is to be effected in respect of size or specification of tires to be manufactured. Moreover, because the assembly or disassembly of the segmented mold is manually carried out within the vulcanizing machine, it is often necessary to wait the required operations until the vulcanizing machine has been sufficiently cooled down, which involves considerable loss time and waste of the heat energy which had been supplied to the vulcanizing machine and used for previous vulcanizing steps.